Illuminating device.



E. 0. SOHWEITZER,

ILLUMINATING DEVICE.

APPLICATION FILED MAR/1, 1912,

@ Patented June 2,1914}.

w l 23AM. m )1 no instance incandescent PATENT UFFIUE.

EDMUND Q. SGHWEITZER, 31? EHICAGU, ILLINOIS, ASSIGNUR T AfifiOCIATED UOMPAINY, 0h @HICAGU, ILLINOIS.

ILLUl/JIINA'KINU' DEVIGE.

specification of itettcrs hatent.

l atented June 2, 1914,

application filed March 4, 1912. serial No. fihLlfil.

To all whom it may concern Be it known that l, Eur/rump 0. Scnwnrruse, a citizen of the United States, residlng at Chicago, in the county of Cook and State it of Illinois, have invented a certain new and ltd forming a part of this specification.

ll/ly' invention relates to illuminating devices and systems and has tor 1ts ob ect the provision of means whereby the failure of one illuminating device of a system "will not "it cause the inoperativeness or failure of other devices of the same system.

One system in which my invention. finds great use is in connection with illuminating systems in which a plurality of devices, "for lamps, are connected in series. To be more specific sp far as this particular application of the invention is concerned, it may be said that in electrical signs tor instance, which are served from 65 an electrical source oft one hundred and titteen volts potential, that ten lamps twelve volts each are preferably connected in series to form a bridge across this source of current. Usually more than one bridge 1s so needed to complete the sign although of course the number of bridges has nothing whatever to do with the invention. These lamps are ct small candle power and are usually of thirty ohms resistance. it Will to be apparent that should one of these lamps become extinguished by reason of the filament breaking or some other detect, that quite a void would be'le'ft in the sign by the entinguishment of this particular lamp and to the other nine lamps in series therewith.

Thus if there were tour bridges in the system the failure of one lamp might nullify the eil'ect oat twenty-five per cent. of the sign, or the failure of merely three lamps at out or" :torty might nullify the efiect of seventyfive per cent. ot" the sign It 1s essential therefore that some means he provided to overcome this very objectionable feature ct the series connection, although to such amangement oi the lamps is by far the most economical in order to secure low candle power lamps, and economical wiring plans. My present invention concerns itself.

with eliminating this defect in the particutt lar instance under consideration, or other equivalent instances as will be readily ap" parent.

1 Generally speaking the form of my inventlon which .l have illustrated herein and WhlChdS one embodiment of my invention comprises suitable means voltage controlled which form a bridge or other satisfactory electrical connection about the-lamp which has failed so that the rest of the lamps may continue burning. The devices operate automatically. ll will describe this embodiment of my invention in connection with. the

, accompanying drawing, in which Figure l is a side View of my improved lamp; Fig. 2 is a sectional view more clearly to reveal the connections; Fig. 3 shows a modification in which two filaments may be used, and Fig. t shows the circuit arrangement, one of the devices having operated.

Referring more particularly to Fig. 1, 1 show a lamp 1. having a filament 2, which filament is associated respectively with the annular screw threaded contact element 3 and the'centrally located connecting stud at as is customary. The lamp, of course, as is customary tits into some suitable receptacle as is well understood so that its elements 3 and 4-. are connected to points of unlike potential to thereby illuminate the lamp. blow in my improved lamp fl. provide additional means which be placed in shunt of the filament 2- whenever this filament breaks. These means are more clearly illustrated in Fig, 2 in which the stud t projects into and is fastened to the normal rear contact ot the lamp. The filament 2 as is apparent, oat course, connects with the shell 3 and contact On top of this contact 5, l mount a dish 5 oil m ate-rial of reasonably high. resistance pref" erably equal to the resistance oi the filament 2. This element 6 may be carbon or other similar material giving the required resistance. The upper surface of this disk '6 is provided with a coating of shellac or lacquer or other insulating material 7. Eurmounting this shellac is a dislr of copper 8. The elements 6, 7 and 8 are prevented from engaging the stud 4 by means of the tube 9 of insulation as shown. Fdurmvounting the copper dish 8 is a sheet of mica l0 and a nut 11 holds all the elements in place upon the stud (e The copper plate 8 by means of a strip '12 is in metal ic connection with the screw threaded she 3 of the lamp. It "will be Normally therefore the circuit of the stud 4:

is through the filament 2 and back to the shell 3. Now should this filament 2 break, then immediately across this bridge or between the elements 8 and 6 a difierence of' potential equal to the total circuit voltage, namely, one hundred and fifteen volts exists as will be readily apparent by inspecting Fig. 4. Now immediately this extreme potential is established across the elements 8 and 6, this potential breaks down the insulation 7 and permits fusion or other satisfactory electrical contact between the elements 8 and 6. The circuit from the stud 4L to the shell 3 may then be traced from the shell 3, strip 12, plate 8, disk 6, conducting plate 5 to the stud 4. In other words there has been substituted in the circuit to replace I the broken filament 2 a high resistance element 6 equal or substantially equal in resistance to the resistance of the filament 2.

In Fig. 3 I have set forth a lamp in which the high resistance element 6 is replaced by a second filament 13, which filamenttakes the place of the ruptured filament so as to continue the illumination of the lamp.

It is of course readily apparent that the parts 6, 7, 8, 9, 10 and 11 may be countersunk within the lamp shell 3, if so desired, to provide a more inclosed article. Likewise these elements may be placed in the socket if desired instead of upon the lamp as will readily suggest itself to those skilled in theart.

In Fig. 4 I have shown the circuit in which a plurality of lamps, indicated by the filaments 2, are shown in series relation with a source of current I l. The spark gaps are illustrated in diagram by the elements 6 and 8 and these elements 6 and 8 are shown as fused together in the right hand lampby the rupture of the right hand filainent 2, thus maintaining the continuity of the circuit without substantial change in the resistance of said circuit.

It will of course be apparent that many modifications within the scope of the appended claims may be made in the specific description above set forth without departing from the spirit of my invention.

Having, however, thus described one embodiment of my invention, What I claim as new and desire to secure by Letters Patent is:

1. An incandescent lamp having a base portion, a centrally located contact terminal thereon, an annular contact element thereon, a pair of terminals on said base separated by aspark gap adapted upon undue rise in potential to connect said centrally located contact with said annular contact, and a stem protruding from said base portion upon which said spark gap terminals are mounted.

2. An incandescent lamp having a base portion, a centrally located contact terminal thereon, an annular contact element thereon, a pair of terminals on said base separated by a spark gap adapted upon undue rise in potential to connect said centrally located contact with said annular contact, and a stem protruding from said base portion upon which said spark gap terminals are mounted, one of said spark gap terminals being normally insulated from said stem.

In witness whereof I hereunto subscribe my name this 17th day of February, A. D., 1912.

MAX W. ZABEL, O. M. lVENNIcH. 

